U.S. patent number 8,342,454 [Application Number 12/826,627] was granted by the patent office on 2013-01-01 for cooling systems.
This patent grant is currently assigned to Paragon Space Development Corporation. Invention is credited to Grant A. Anderson, Thomas Orville Leimkuehler, Thomas William Morin.
United States Patent |
8,342,454 |
Leimkuehler , et
al. |
January 1, 2013 |
**Please see images for:
( Certificate of Correction ) ** |
Cooling systems
Abstract
A portable thermal-control system adapted to support
space-related research and exploration. Embodiments of the present
invention assist in preventing overheating of small payloads being
transported from an orbiting space vehicle to a planetary surface
by small atmospheric-entry vehicles. Other embodiments of the
present invention provide thermal control within an extra-vehicular
activity (EVA) suit. Each embodiment utilizes at least one
phase-change material, cooled significantly below the freezing
temperature, to absorb heat.
Inventors: |
Leimkuehler; Thomas Orville
(League City, TX), Morin; Thomas William (Vail, AZ),
Anderson; Grant A. (Tucson, AZ) |
Assignee: |
Paragon Space Development
Corporation (Tucson, AZ)
|
Family
ID: |
47388179 |
Appl.
No.: |
12/826,627 |
Filed: |
June 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61221531 |
Jun 29, 2009 |
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Current U.S.
Class: |
244/171.7;
244/159.1 |
Current CPC
Class: |
B64G
1/50 (20130101); B64G 1/62 (20130101); B64G
6/00 (20130101) |
Current International
Class: |
B64G
1/58 (20060101) |
Field of
Search: |
;244/171.8,171.7,159.1,121,117A,57 ;165/104.17,104.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Dinh; Tien
Assistant Examiner: Green; Richard R
Attorney, Agent or Firm: Stoneman Law Patent Group Stoneman;
Martin L. Liudahl; Kyle
Government Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Some embodiments of this invention may have been developed with
United States Government support under Contract No. NNX08CC35P and
Contract No. NNX09RA19C awarded by The National Aeronautics and
Space Administration. The Government may have certain rights in the
invention.
Claims
What is claimed is:
1. A system, relating to assisting preventing overheating of at
least one payload being transported from at least one on-orbit
deployer to a planetary surface by at least one atmospheric-entry
vehicle, comprising: a) situated within the at least one
atmospheric-entry vehicle between at least one payload compartment
for the at least one payload and at least one forward
atmospheric-entry structure at the forward end of the vehicle
producing atmospheric-entry heat during such atmospheric entry, at
least one intermediate structure; b) wherein said at least one
intermediate structure comprises at least one cooling component; c)
wherein said at least one cooling component comprises at least one
phase-change material cooled to solid state; d) wherein said at
least one intermediate structure is structured and arranged to
assist absorbing the atmospheric-entry heat coupled with
sensible-heat processes and latent-heat processes; e) wherein such
sensible-heat processes are effected by transition of said at least
one phase-change material from at least one sub-phase-change
temperature to a higher temperature; f) wherein such latent-heat
processes are structured and arranged to be effected by phase
transition of said at least one phase-change material from
solid-state to liquid-state; and g) wherein overheating of such at
least one payload being transported to the planetary surface by the
at least one atmospheric-entry vehicle is assisted to be prevented
during such atmospheric entry; h) wherein said at least one
phase-change material is predominantly water.
2. The system according to claim 1 wherein said at least one
intermediate structure further comprises: a) at least one container
structured and arranged to contain said at least one cooling
component; b) wherein said at least one container comprises at
least one heat-exchanging wall structured and arranged to assist
thermal exchange between said at least one phase-change material
and at least one thermal environment adjacent said at least one
heat-exchanging wall; c) wherein said at least one cooling
component further comprises at least one locator structured and
arranged to locate said at least one phase-change material in
direct thermal interaction with said at least one heat-exchanging
wall; and d) wherein said at least one locator comprises at least
one volumetric accommodator structured and arranged to accommodate
volumetric changes of said phase-change material during phase
transition.
3. The system according to claim 2 wherein said at least one
intermediate structure further comprises: a) at least one forward
coupler structured and arranged to assist coupling of said at least
one intermediate structure with the at least one forward
atmospheric-entry structure; and b) at least one aft coupler
structured and arranged to detachably couple said intermediate
structure to at least one open forward end of the at least one
payload compartment; c) wherein said at least one forward coupler
comprises at least one thermal isolator structured and arranged to
thermally isolate non-coupled portions of said at least one
intermediate structure from the atmospheric-entry heat generated by
the at least one forward atmospheric-entry structure during such
atmospheric entry; and d) wherein said at least one aft coupler
comprises at least one postioner structured and arranged to assist
positioning of said at least one heat-exchanging wall in thermal
interaction with at least one thermal environment of the at least
one payload compartment.
4. The system according to claim 3 wherein said at least one
intermediate structure further comprises: a) at least one aft
mating surface structured and arranged to assist forming at least
one mated engagement with at least one pressure-retaining seal of
the at least one open forward end; b) wherein mating of said at
least one mating surface with the at least one pressure-retaining
seal assists in maintaining at least one generally isobaric
pressure level within the at least one thermal environment of the
at least one payload compartment; c) wherein said at least one aft
coupler comprises at least one first releasable mechanical retainer
structured and arranged to assist releasable mechanical retention
of said at least one intermediate structure to the at least one
open forward end of the at least one payload compartment; and d)
wherein said at least one intermediate structure defines at least
one detachable lid structured and arranged to detachably lid the at
least one forward open end of the at least one payload
compartment.
5. The system according to claim 4 wherein said at least one
container further comprises: a) at least one forward open end, at
least one closed aft end, and at least one peripheral side wall
extending between said at least one forward open end and said at
least one closed aft end; b) at least one removable cover
structured and arranged to removably cover said at least one open
forward end; and c) at least one second releasable mechanical
retainer structured and arranged to assist releasable mechanical
retention of said at least one removable cover to said at least one
forward open end of said at least one container.
6. The system according to claim 5 wherein said at least one closed
aft end comprises said at least one heat-exchanging wall.
7. The system according to claim 6 said at least one closed aft end
further comprises, engaged within said phase-change material, at
least one heat transfer fin structured and arranged to provide at
least one supplementary pathway of heat transfer between said
phase-change material and said at least one heat-exchanging
wall.
8. The system according to claim 7 wherein said at least one
locator further comprises at least one insulator structured and
arranged to reduce a rate of thermal migration of the
atmospheric-entry heat across said at least one intermediate
structure.
9. The system according to claim 8 wherein said at least one
locator comprises at least one compressible foamed elastomeric
material.
10. The system according to claim 7 wherein said at least one
phase-change material comprises an initial temperature of between
about -1 degree Celsius and about -150 degrees Celsius.
11. The system according to claim 10 wherein said at least one
cooling component is structured and arranged to contain about
one-half pound of said at least one phase-change material.
12. The system according to claim 7 wherein said at least one first
releasable mechanical retainer and said at least one second
releasable mechanical retainer comprise threaded fasteners.
13. The system according to claim 6 wherein: a) said at least one
forward open end comprises at least one peripheral engagement
surface structured and arranged to engage said at least one
removable cover; and b) said at least one peripheral engagement
surface comprises at least one fluid-retaining seal structured and
arranged to form at least one fluid-retaining seal between said at
least one forward open end and said at least one removable
cover.
14. A system, relating to assisting preventing overheating of at
least one payload being transported from space to a planetary
surface within at least one payload compartment of at least one
atmospheric-entry vehicle, comprising: a) situated within the at
least one atmospheric-entry vehicle between the at least one
payload compartment and at least one forward atmospheric-entry
structure at the forward end of the vehicle producing
atmospheric-entry heat during such atmospheric entry, at least one
payload-compartment lid structured and arranged to lid the at least
one payload compartment; b) wherein said at least one
payload-compartment lid comprises at least one cooling component
and at least one internal container structured and arranged to
contain said at least one cooling component; c) wherein said at
least one cooling component comprises at least one phase-change
material cooled to solid state; d) wherein said at least one
payload-compartment lid is structured and arranged to assist
absorbing the atmospheric entry heat coupled with sensible-heat
processes and latent-heat processes; e) wherein such sensible-heat
processes are structured and arranged to be effected by transition
of said at least one phase-change material from at least one
sub-phase-change temperature to a higher temperature; f) wherein
such latent-heat processes are structured and arranged to be
effected by phase transition of said at least one phase-change
material from solid-state to liquid-state; and g) wherein
overheating of such at least one payload being transported to the
planetary surface by the at least one atmospheric-entry vehicle is
assisted to be prevented during such atmospheric entry; h) wherein
said at least one phase-change material is predominantly water.
15. The system according to claim 14 wherein said at least one
internal container comprises: a) at least one heat-exchanging wall
structured and arranged to assist thermal exchange between said at
least one phase-change material and at least one thermal
environment within the at least one payload compartment; b) wherein
said at least one cooling component further comprises at least one
locator structured and arranged to locate said at least one
phase-change material in direct thermal interaction with said at
least one heat-exchanging wall; and c) wherein said at least one
locator comprises at least one elastomeric foam material structured
and arranged to accommodate volumetric changes of said phase-change
material during phase transition.
16. The system according to claim 15 wherein said at least one
payload-compartment lid further comprises: a) at least one forward
coupler structured and arranged to assist coupling of said at least
one intermediate structure with the at least one forward
atmospheric-entry structure; and b) at least one aft coupler
structured and arranged to detachably couple said at least one
payload-compartment lid to at least one open forward end of the at
least one payload compartment; c) wherein said at least one forward
coupler comprises at least one thermal isolator structured and
arranged to thermally isolate non-coupled portions of said at least
one intermediate structure from the atmospheric-entry heat during
generated by the at least one forward atmospheric-entry structure
during such atmospheric entry; and d) wherein said at least one aft
coupler is structured and arranged to position said at least one
heat-exchanging wall in thermal interaction with at least one
thermal environment of the at least one payload compartment.
17. The system according to claim 16 wherein said at least one
payload-compartment lid further comprises: a) at least one aft
mating surface structured and arranged to assist forming at least
one mated engagement with at least one pressure-retaining seal of
the at least one open forward end; b) wherein such mating of said
at least one mating surface with the at least one
pressure-retaining seal assists in maintaining at least one
generally isobaric pressure level within the at least one thermal
environment of the at least one payload compartment; and c) wherein
said at least one aft coupler comprises at least one first threaded
retainer structured and arranged to assist threaded retention of
said at least one payload-compartment lid to the at least one open
forward end of the at least one payload compartment.
18. The system according to claim 17 wherein said at least one
container further comprises: a) at least one forward open end, at
least one closed aft end, and at least one peripheral side wall
extending between said at least one forward open end and said at
least one closed aft end; b) at least one removable cover
structured and arranged to removably cover said at least one open
forward end; and c) at least one second threaded retainer
structured and arranged to assist threaded retention of said at
least one removable cover to said at least one forward open
end.
19. The system according to claim 18 wherein said at least one
closed aft end comprises said at least one heat-exchanging
wall.
20. The system according to claim 19 wherein: a) said at least one
forward open end comprises at least one peripheral engagement
surface structured and arranged to engage said at least one
removable cover; and b) said at least one peripheral engagement
surface comprises at least one fluid-retaining seal structured and
arranged to form at least one fluid-retaining seal between said at
least one forward open end and said at least one removable cover.
Description
CROSS-REFERENCE TO RELATED APPLICATION
The present application is related to and claims priority from
prior provisional application Ser. No. 61/221,531, filed Jun. 29,
2009, entitled "COOLING SYSTEMS", the contents of which is
incorporated herein by this reference and is not admitted to be
prior art with respect to the present invention by the mention in
this cross-reference section.
BACKGROUND
This invention relates to cooling systems. More particularly, this
invention relates to portable thermal-control systems adapted to
support space-related research, space exploration, and operations
in thermally-demanding earth environments.
The need for thermal control has been apparent from the beginning
of space research and exploration. From the early Gemini program
through the interplanetary missions currently in design,
thermal-control hardware has existed as a primary subsystem in
space-operated technologies. Space vehicles must be engineered to
withstand the demanding environment of space, and depending on
mission profile, reentry through a planetary atmosphere. Such space
vehicles are comprised of an array of components, which operate
effectively and reliably only when maintained within specified
thermal design limits. Furthermore, space vehicles often function
to transport human crew and other thermally-sensitive payload.
The establishment of a long-term space presence is an important
human endeavor and represents a significant investment of
resources. To maximize the return on such an investment, it is
important to develop efficient means for implementing relatively
frequent return of scientific materials and other payloads from
on-orbit stations to Earth. The development of small down-mass
re-entry vehicles, to provide for the quick return of payloads from
space, would be one viable solution, if an effective means for
thermal control during the return procedure were to exist for such
hardware.
Similar technical challenges exist in other space-deployed systems,
including, thermal control of extra-vehicular activity (EVA) suits
worn during on-orbit operations and during surface missions on
other space bodies (for example, the Moon and Mars). Clearly, the
development of more efficient portable thermal-control subsystems,
especially those adapted to support space-related research, space
exploration, and similar applications would be of great benefit to
many.
OBJECTS AND FEATURES OF THE INVENTION
A primary object and feature of the present invention is to provide
a system overcoming the above-mentioned problems. It is a further
object and feature of the present invention to provide such a
system that assists in preventing overheating of payloads being
transported from an on-orbit deployer to a planetary (or moon)
surface by an atmospheric-entry vehicle. It is another object and
feature of the present invention to provide such a system adapted
to provide thermal control of an EVA suit. It is a further object
and feature of the present invention to provide such a system
adapted to control thermal environments using latent-heat processes
associated with at least one Phase Change Material (PCM). It is
another object and feature of the present invention to provide such
a system usable to control thermal environments using both
sensible-heat process and latent-heat processes provided by at
least one PCM cooled to below the material's isothermic
phase-change temperature.
It is an additional object and feature of the present invention to
provide such a system adapted to use water as the PCM. It is
another object and feature of the present invention to provide such
a system adapted to control the expansion of a water-based PCM
during phase transition of the PCM between a liquid state and solid
state. A further primary object and feature of the present
invention is to provide such a system that is efficient,
cost-effective, and useful. Other objects and features of this
invention will become apparent with reference to the following
descriptions.
SUMMARY OF THE INVENTION
In accordance with a preferred embodiment hereof, this invention
provides a system, relating to assisting preventing overheating of
at least one payload being transported from at least one on-orbit
deployer to a planetary surface, or other atmosphere-shrouded body,
by at least one atmospheric-entry vehicle, comprising: situated
within the at least one atmospheric-entry vehicle between at least
one payload compartment for the at least one payload and at least
one forward atmospheric-entry structure producing atmospheric-entry
heat during such atmospheric entry, at least one intermediate
structure; wherein such at least one intermediate structure
comprises at least one cooling component; wherein such at least one
cooling component comprises at least one phase-change material
cooled to solid state; wherein such at least one intermediate
structure is structured and arranged to assist absorbing the
atmospheric entry heat coupled with sensible-heat processes and
latent-heat processes; wherein such sensible-heat processes are
effected by transition of such at least one phase-change material
from at least one sub-phase-change temperature (below 0.degree. C.
for water-based materials) to a higher temperature; wherein such
latent-heat processes are structured and arranged to be effected by
phase transition of such at least one phase-change material from
solid-state to liquid-state; and wherein overheating of such at
least one payload being transported to the planetary surface, or
other atmosphere-shrouded body, by the at least one
atmospheric-entry vehicle is assisted to be prevented during such
atmospheric entry.
Moreover, it provides such a system wherein such at least one
phase-change material comprises substantially water. Additionally,
it provides such a system wherein such at least one intermediate
structure further comprises: at least one container structured and
arranged to contain such at least one cooling component; wherein
such at least one container comprises at least one heat-exchanging
wall structured and arranged to assist thermal exchange between
such at least one phase-change material and at least one thermal
environment adjacent such at least one heat-exchanging wall;
wherein such at least one cooling component further comprises at
least one locator structured and arranged to locate such at least
one phase-change material in direct thermal interaction with such
at least one heat-exchanging wall; wherein such at least one
locator comprises at least one volumetric accommodator structured
and arranged to accommodate volumetric changes of such phase-change
material during phase transition. Also, it provides such a system
wherein such at least one intermediate structure further comprises:
at least one forward coupler structured and arranged to assist
coupling of such at least one intermediate structure with the at
least one forward atmospheric-entry structure; and at least one aft
coupler structured and arranged to detachably couple such
intermediate structure to at least one open forward end of the at
least one payload compartment; wherein such at least one forward
coupler comprises at least one thermal isolator structured and
arranged to thermally isolate non-coupled portions of such at least
one intermediate structure from the atmospheric-entry heat during
generated by the at least one forward atmospheric-entry structure
during such atmospheric entry; and wherein such at least one aft
coupler comprises at least one postioner structured and arranged to
assist positioning of such at least one heat-exchanging surface in
thermal interaction with at least one thermal environment of the at
least one payload compartment.
In addition, it provides such a system wherein such at least one
intermediate structure further comprises: at least one aft mating
surface structured and arranged to assist forming at least one
mated engagement with at least one pressure-retaining seal of the
at least one open forward end; wherein such mating of such at least
one mating surface with the at least one pressure-retaining seal
assists in maintaining generally isobaric pressure levels within
the at least one thermal environment of the at least one payload
compartment; wherein such at least one aft coupler comprises at
least one first plurality of releasable mechanical retainers
structured and arranged to assist releasable mechanical retention
of such at least one intermediate structure to the at least one
open forward end of the at least one payload compartment; and
wherein such at least one intermediate structure defines at least
one detachable lid structured and arranged to detachably lid the at
least one forward open end of the at least one payload compartment.
And, it provides such a system wherein such at least one container
further comprises: at least one forward open end, at least one
closed aft end, and at least one peripheral side wall extending
between such at least one forward open end and such at least one
closed aft end; at least one removable cover structured and
arranged to removably cover such at least one open forward end; and
at least one second plurality of releasable mechanical retainers
structured and arranged to assist releasable mechanical retention
of such at least one removable cover to such at least one forward
open end of such at least one container. Further, it provides such
a system wherein such at least one closed aft end comprises such at
least one heat-exchanging wall.
Even further, it provides such a system wherein such at least one
closed aft end further comprises, engaged within such phase-change
material, at least one heat transfer fin structured and arranged to
provide at least one supplementary pathway of heat transfer between
such phase-change material and such at least one heat-exchanging
wall. Moreover, it provides such a system wherein: such at least
one forward open end comprises at least one peripheral engagement
surface structured and arranged to engage such at least one
removable cover; and such at least one peripheral engagement
surface comprises at least one pressure-retaining seal structured
and arranged to form at least one pressure-retaining seal between
such at least one forward open end and such at least one removable
cover. Additionally, it provides such a system wherein such at
least one locator further comprises at least one insulator
structured and arranged to reduce a rate of thermal migration of
the atmospheric-entry heat across such at least one intermediate
structure. Also, it provides such a system wherein such at least
one locator comprises at least one foamed elastomeric material.
And, it provides such a system wherein such at least one
phase-change material is cooled to comprise an initial temperature
of between about -1 degrees Celsius and about -150 degrees Celsius.
Further, it provides such a system wherein such at least one
cooling component is structured and arranged to contain about
one-half pound of such at least one phase-change material. Even
further, it provides such a system wherein such first plurality of
releasable mechanical retainers and such second plurality of
releasable mechanical retainers comprise externally threaded
fasteners.
In accordance with another preferred embodiment hereof, this
invention provides a system, relating to assisting preventing
overheating of at least one payload being transported from space to
a planetary surface, or other atmosphere-shrouded body, within at
least one payload compartment of at least one atmospheric-entry
vehicle, comprising: situated within the at least one
atmospheric-entry vehicle between the at least one payload
compartment and at least one forward atmospheric-entry structure
producing atmospheric-entry heat during such atmospheric entry, at
least one payload-compartment lid structured and arranged to lid
the at least one payload compartment; wherein such at least one
payload-compartment lid comprises at least one cooling component
and at least one internal container structured and arranged to
contain such at least one cooling component; wherein such at least
one cooling component comprises at least one phase-change material
cooled to solid state; wherein such at least one
payload-compartment lid is structured and arranged to assist
absorbing the atmospheric entry heat coupled with sensible-heat
processes and latent-heat processes; wherein such sensible-heat
processes are effected by transition of such at least one
phase-change material from at least one cooled temperature to a
higher temperature; wherein such latent-heat processes are
structured and arranged to be effected by phase transition of such
at least one phase-change material from solid-state to
liquid-state; and wherein overheating of such at least one payload
being transported to the planetary surface, or other
atmosphere-shrouded body, by the at least one atmospheric-entry
vehicle is assisted to be prevented during such atmospheric
entry.
Moreover, it provides such a system wherein such at least one
phase-change material comprises substantially water. Additionally,
it provides such a system wherein such at least one internal
container comprises: at least one heat-exchanging wall structured
and arranged to assist thermal exchange between such at least one
phase-change material and at least one thermal environment within
the at least one payload compartment; wherein such at least one
cooling component further comprises at least one locator structured
and arranged to locate such at least one phase-change material in
direct thermal interaction with such at least one heat-exchanging
wall; wherein such at least one locator comprises at least one
elastomeric foam material structured and arranged to accommodate
volumetric changes of such phase-change material during phase
transition. Also, it provides such a system wherein such at least
one payload-compartment lid further comprises: at least one forward
coupler structured and arranged to assist coupling of such at least
one intermediate structure with the at least one forward
atmospheric-entry structure; and at least one aft coupler
structured and arranged to detachably couple such at least one
payload-compartment lid to at least one open forward end of the at
least one payload compartment; wherein such at least one forward
coupler comprises at least one thermal isolator structured and
arranged to thermally isolate non-coupled portions of such at least
one intermediate structure from the atmospheric-entry heat during
generated by the at least one forward atmospheric-entry structure
during such atmospheric entry; and wherein such at least one aft
coupler is structured and arranged to position such at least one
heat-exchanging surface in thermal interaction with at least one
thermal environment of the at least one payload compartment.
In addition, it provides such a system wherein such at least one
payload-compartment lid further comprises: at least one aft mating
surface structured and arranged to assist forming at least one
mated engagement with at least one pressure-retaining seal of the
at least one open forward end; wherein such mating of such at least
one mating surface with the at least one pressure-retaining seal
assists in maintaining generally isobaric pressure levels within
the at least one thermal environment of the at least one payload
compartment; and wherein such at least one aft coupler comprises at
least one first plurality of threaded retainers structured and
arranged to assist threaded retention of such at least one
payload-compartment lid to the at least one open forward end of the
at least one payload compartment. And, it provides such a system
wherein such at least one container further comprises: at least one
forward open end, at least one closed aft end, and at least one
peripheral side wall extending between such at least one forward
open end and such at least one closed aft end; at least one
removable cover structured and arranged to removably cover such at
least one open forward end; and at least one second plurality of
threaded retainers structured and arranged to assist threaded
retention of such at least one removable cover to such at least one
forward open end. Further, it provides such a system wherein such
at least one closed aft end comprises such at least one
heat-exchanging wall.
Even further, it provides such a system wherein: such at least one
forward open end comprises at least one peripheral engagement
surface structured and arranged to engage such at least one
removable cover; and such at least one peripheral engagement
surface comprises at least one pressure-retaining seal structured
and arranged to form at least one pressure-retaining seal between
such at least one forward open end and such at least one removable
cover.
In accordance with another preferred embodiment hereof, this
invention provides a system, relating to providing at least one
portable cooling system, comprising: at least one container
structured and arranged to contain at least one phase-change
material having at least one liquid state and at least one solid
state; wherein such at least one container comprises at least one
fluid-retaining boundary structured and arranged to retain the at
least one phase-change material in the at least one liquid state
and the at least one solid state, at least one heat-transfer
interface structured and arranged to establish at least one
physical interface enabling heat transfer across such at least one
fluid-retaining boundary, wherein such at least one heat-transfer
interface comprises, structured and arranged to be embedded within
multiple locations within the at least one phase-change material,
at least one heat-transfer as sister structured and arranged to
assist heat transfer between the at least one phase-change material
and such at least one heat-transfer interface; wherein such at
least one heat-transfer assister comprises at least one mechanical
disrupter structured and arranged to assist mechanical disruption
of crystalline lattices occurring within the at least one
phase-change material during at least one phase-change transition
from the at least one liquid state to the at least one solid
state.
Even further, it provides such a system wherein: such at least one
fluid-retaining boundary comprises a plurality of interior surfaces
in physical contact with the at least one phase-change material;
such at least one heat-transfer assister comprises at least one
plurality of projecting fins; each projecting fin of such at least
one plurality of projecting fins comprises a plurality of
heat-exchanging surfaces, each one structured and arranged to
assist exchanges of heat energy between the at least one
phase-change material and such projecting fin; wherein each
heat-exchanging surface comprises a non-parallel orientation
relative to all opposing adjacent interior surfaces of such
plurality of interior surfaces and all opposing adjacent
heat-exchanging surfaces of such plurality of heat-exchanging
surfaces; and such non-parallel orientation of such respective
opposing surfaces produces mechanically-disruptive movement of the
crystalline lattices occurring within the at least one phase-change
material during such at least one phase-change transition from the
at least one liquid state to the at least one solid state. Even
further, it provides such a system wherein each such projecting fin
comprises: at least one proximal end portion joined with such at
least one heat-transfer interface, at least one distal end, at
least one longitudinal length separating such at least one proximal
end and such at least one distal end; and within such at least one
longitudinal length, at least one parallelogram-shaped lateral
cross-section. Even further, it provides such a system wherein each
such projecting fin tapers from such at least one proximal end to
such at least one distal end. Even further, it provides such a
system further comprising: within such at least one fluid-retaining
boundary, at least one expandable fold structured and arranged to
assist articulated expansion of portions of such at least one
fluid-retaining boundary; wherein volumetric changes of such
phase-change material during such phase transition are accommodated
by such articulated expansion of such at least one fluid-retaining
boundary.
Even further, it provides such a system further comprising: at
least one protective outer shell structured and arranged to
protectively enclose portions of such at least one fluid-retaining
boundary; wherein such at least one outer shell comprises a fixed
external volume; and disposed between such portions of such at
least one fluid-retaining boundary and such at least one outer
shell, at least one resiliently-deformable member structured and
arranged to provide at least one region of resiliently-deformable
volumetric expansion between such at least one expandable fold and
such at least one outer shell. Even further, it provides such a
system wherein such at least one resiliently-deformable member
comprises at least one compressible foam. Even further, it provides
such a system wherein such at least one fluid-retaining boundary
comprises at least one flexible polyvinyl fluoride sheet. Even
further, it provides such a system further comprising: such at
least one phase-change material; wherein such at least one
phase-change material comprises substantially water. Even further,
it provides such a system wherein such at least one phase-change
material comprises at least one cooled temperature below an
isothermic phase change temperature of such at least one
phase-change material.
In accordance with another preferred embodiment hereof, this
invention provides a system, relating to assisting preventing
overheating of at least one payload being transported from space to
a planetary surface, or other atmosphere-shrouded body, within at
least one payload compartment of at least one atmospheric-entry
vehicle, comprising: situated within the at least one
atmospheric-entry vehicle between the at least one payload
compartment and at least one forward atmospheric-entry structure
producing atmospheric-entry heat during such atmospheric entry, lid
means for lidding the at least one payload compartment; wherein
such lid means comprises cooling means for cooling and container
means for containing such cooling means; wherein such cooling means
comprises at least one phase-change material cooled to solid state;
wherein such lid means assists absorbing the atmospheric entry heat
coupled with sensible-heat processes and latent-heat processes;
wherein such sensible-heat processes are effected by transition of
such at least one phase-change material from at least one
sub-phase-change temperature to a higher temperature; wherein such
latent-heat processes are structured and arranged to be effected by
phase transition of such at least one phase-change material from
solid-state to liquid-state; and wherein overheating of such at
least one payload being transported to the planetary surface, or
other atmosphere-shrouded body, by the at least one
atmospheric-entry vehicle is assisted to be prevented during such
atmospheric entry. In addition, it provides each and every novel
feature, element, combination, step and/or method disclosed or
suggested by this patent application.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic diagram, illustrating a payload being
transported from an on-orbit deployer to a planetary surface, or
other atmosphere-shrouded body, by atmospheric-entry vehicle,
according to a preferred application of the present invention.
FIG. 2 shows a side view, diagrammatically illustrating the
integration of a Payload Containment and Thermal Control Unit
(PCTCU) within the atmospheric entry vehicle, comprising a
preferred embodiment of the present invention.
FIG. 3 shows a partial perspective view, of the PCTCU with the
outer structures of the atmospheric entry vehicle removed to expose
a Thermal Control Unit (TCU), according to a preferred embodiment
of the present invention.
FIG. 4 shows a side elevational view of the TCU, mounted operably
to a forward end of a payload compartment of the PCTCU, according
to the preferred embodiment of FIG. 2.
FIG. 5 shows a sectional view, through the section 5-5 of FIG. 4,
generally illustrating preferred component arrangements of the
PCTCU, according to the preferred embodiment of FIG. 2.
FIG. 6A shows an exploded view of the PCTCU, according to the
preferred embodiment of FIG. 2.
FIG. 6B shows a partial exploded view, of Detail 6B of FIG. 6A,
illustrating the forward end of PCTCU, with the components of the
TCU magnified for clarity of description, according to a preferred
embodiment of the present invention.
FIG. 7 shows a partial sectional view, of the sectional Detail 7 of
FIG. 5, further illustrating the forward end of PCTCU, with the
components of the TCU magnified for clarity of description,
according to a preferred embodiment of the present invention.
FIG. 8A shows a plan view of a forward wall of the TCU, according
to the preferred embodiment of FIG. 2.
FIG. 8B shows a plan view of an aft wall of the TCU, according to
the preferred embodiment of FIG. 2.
FIG. 9 shows an extra-vehicular activity (EVA) suit comprising a
portable life support system (PLSS) utilizing an alternate
embodiment of the thermal-control system, according to a preferred
application of the present invention.
FIG. 10 shows a rear view, diagrammatically illustrating the
integration of an alternate Thermal Control Unit (TCU) within the
PLSS "pack" of the EVA suit, according to a preferred embodiment of
the present invention.
FIG. 11 shows a sectional view, through the section 11-11 of FIG.
10, generally illustrating preferred component arrangements of the
TCU, according to the preferred embodiment of FIG. 10.
FIG. 12 shows a sectional view, through the section 12-12 of FIG.
11, generally illustrating preferred component arrangements of the
TCU, according to the preferred embodiment of FIG. 10.
FIG. 13 shows a partial sectional view, of the sectional detail 13
of FIG. 12, magnified for clarity of description according to a
preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE BEST MODES AND PREFERRED EMBODIMENTS OF
THE INVENTION
Thermal-control system 100 comprises a series of system embodiments
designed primarily to support thermal control in space-related
research and exploration applications. One highly preferred
embodiment of the present invention assists in preventing
overheating of small payloads transported from an orbiting space
vehicle to a planetary surface (or other space body comprising an
atmosphere) by a small atmospheric-entry vehicle. Other preferred
embodiments of the present invention provide thermal control within
an extra-vehicular activity (EVA) suit. Each embodiment of
thermal-control system 100 preferably utilizes at least one
phase-change material (PCM) to absorb heat. More preferably, each
embodiment is preferably configured to utilize at least one PCM to
absorb heat through both sensible and latent heat processes. It
should be noted that useful applications of the present technology
extend beyond space exploration and research, having preferred
application in thermally demanding earth-based environments.
Secondary useful applications may include thermally-controlled
suits for firefighters, cooling of electric vehicle systems,
etc.
FIG. 1 shows a schematic diagram, illustrating transport of a
payload 104 from an on-orbit deployer 106 to a planetary surface
108 by atmospheric-entry vehicle 110, according to a preferred
application of the present invention. FIG. 2 shows a side view,
diagrammatically illustrating the integration of a Payload
Containment and Thermal Control Unit (hereinafter referred to as
PCTCU 103) within atmospheric-entry vehicle 110, according to a
preferred embodiment of the present invention. In the present
disclosure, the term "planetary" shall be broadly defined to
include other celestial bodies comprising enveloping atmospheres,
such as, for example dwarf planets, satellites of other planets,
small solar system bodies, asteroids, trans-neptunian objects,
comets, and other atmosphere-shrouded bodies.
Atmospheric-entry vehicle 110 is preferably designed to routinely
return small payloads from on-orbit deployer 106, such as, for
example, a space station, or similar orbiting space structure. Such
small down-mass systems provide a means for quickly returning
materials to Earth, thereby reducing dependence on larger transport
systems, which generally operate on infrequent transfer
schedules.
PCTCU 103 is preferably designed to maintain the internal payload
104 within specified thermal design limits during an atmospheric
return and recovery procedure, as shown. Some of the specific types
of payloads supported by the system are refrigerated samples,
frozen samples, and cryogenic samples.
In a representative return procedure 112, atmospheric-entry vehicle
110 is deployed from on-orbit deployer 106 and is preferably
equipped to perform one or more on-orbit maneuvers 114 to establish
an appropriate approach for atmospheric entry. Following the
orbital stage, atmospheric-entry vehicle 110 enters
atmospheric-entry stage 118, as diagrammatically depicted in FIG.
1.
Proposed configurations of atmospheric-entry vehicle 110 include
the use of a Tube Deployed Return Vehicle (identified herein as
TDRV 115) having a blunt nose cap 121 in combination with one or
more deployable drag structures, which may include a skirt-like
flair 116 that unfold during the decent, as shown. TDRV 115
traverses a broad range of Mach numbers during atmospheric entry
stage 118 (from approximately 20-Mach at entry to subsonic after
about one-hundred-thirty-five seconds). Such atmospheric entry
subjects forward atmospheric-entry structures of the vehicle
(particularly nose cap 121) to significant heating. Applicant's
computer-assisted thermal modeling of TDRV 115 during return
procedure 112 identified re-entry stage 118 as the primary heating
domain of TDRV 115, with nose cap 121 generating a significant
portion the anticipated thermal load.
In final stages of return procedure 112, TDRV 115 is further
decelerated by parachute deployment, as shown, or by other landing
techniques. On reaching the planetary surface 108, TDRV 115 along
with payload 104 are available for recovery. Under appropriate
circumstances, PCTCU 103, preferably including TCU 102, may be
reconditioned for reuse. Furthermore, upon reading this
specification, those with ordinary skill in the art will now
appreciate that, under appropriate circumstances, considering such
issues as field of operation, science objectives, advances in
vehicle technology, etc., other mission profiles such as, for
example, utilizing a TDRV/PCTCU-based system to deploy a
surface-conducted experiment from orbit, utilizing a direct
(non-orbital) entry approach, utilizing other vehicle
configurations, etc., may suffice.
PCTCU 103 preferably comprises at least one self-contained cooling
component, most preferably in the form of a demountable Thermal
Control Unit (hereinafter referred to as TCU 102). TCU 102 is
preferably situated within atmospheric-entry vehicle 110 in
intermediate position 125 between payload compartment 120
(containing payload 104) and nose cap 121, as shown in FIG. 1. This
preferred intermediate position places TCU 102 (at least embodying
herein such at least one intermediate structure) between payload
104 and the forward atmospheric-entry structures identified in
Applicant's thermal studies to be primary contributors of
atmospheric-entry heat during return procedure 112. In the present
disclosure, nose cap 121 at least embodies herein at least one
forward atmospheric-entry structure producing atmospheric-entry
heat during such atmospheric entry.
FIG. 3 shows a partial perspective view of the forward end of PCTCU
103, with the surrounding structures of TDRV 115 removed to expose
the disk-shaped TCU 102. The following sections of the present
teachings will focus on the preferred structures and functions of
TCU 102 as a primary preferred embodiment of the present invention.
FIG. 4 shows a side elevational view of TCU 102, mounted operably
to forward end 122 of payload section 124 of PCTCU 103, according
to the preferred embodiment of FIG. 2. FIG. 5 shows a sectional
view, through the section 5-5 of FIG. 4, generally illustrating
preferred component arrangements of PCTCU 103, according to the
preferred embodiment of FIG. 2.
One preferred configuration of PCTCU 103 divides the structure into
two main subcomponents, preferably comprising TCU 102 and payload
section 124, as shown. Payload section 124 is further divided into
a forward payload compartment 120 and aft section 128 by a
transverse mid plate 130, as shown. Payload compartment 120
preferably functions to house the returning payload materials, with
aft section 128 functioning to accommodate avionics, parachute
package, and similar components. Payload section 124 preferably
comprises a generally cylindrical shape preferably comprising an
open forward end 132 (best viewed in FIG. 6B) to provide external
access to the interior of payload compartment 120, as shown. Upon
reading this specification, those with ordinary skill in the art
will now appreciate that, under appropriate circumstances,
considering such issues as design preference, user preferences,
marketing preferences, cost, structural requirements, available
materials, technological advances, etc., other shape arrangements
such as, for example, spherical bodies, tapered bodies,
asymmetrical lifting bodies, etc., may suffice.
One preferred configuration of PCTCU 103, TCU 102 comprises an
assembled height A of about 1 inch and an approximately circular
diameter B of about 31/4 inches. This physical configuration was
identified as being useful for the intended small down-mass
transport of scientific materials from orbit. It is noted that the
preferred configuration of TCU 102 is scalable to produce alternate
preferred embodiments of larger or smaller thermal capacity.
In addition to functioning as a self-contained cooling component,
TCU 102 is preferably configured to function as a detachable lid
134 for payload compartment 120, as shown. This preferred
arrangement functions both to reduce redundancy of system
components and place heat-transfer structures of TCU 102 in direct
thermal interaction with the internal environment of payload
compartment 120 (at least embodying herein wherein such at least
one intermediate structure defines at least one detachable lid
structured and arranged to detachably lid the at least one forward
open end of the at least one payload compartment).
FIG. 6A shows an exploded view of PCTCU 103, according to the
preferred embodiment of FIG. 2. FIG. 6B shows a partial exploded
view, of the Detail 6B of FIG. 6A, illustrating the forward end of
PCTCU 103, with preferred components of TCU 102 magnified for
clarity of description according to a preferred embodiment of the
present invention.
TCU 102 preferably comprises a housing 138 having a forward open
end 140, closed aft end 142, and a continuous peripheral sidewall
144 extending between the two structures, as shown. A removable
cover plate 152 is preferably fitted to open end 140 to fully
enclose a preferred cooling component 150 within a fully enclosed
internal chamber 146, as shown. Forward open end 140 of housing 138
preferably comprises a peripheral engagement surface 155 structured
and arranged to engage the undersurface 156 of cover plate 152, as
shown. The interface of peripheral engagement surface 155 and
undersurface 156 is preferably configured to form a continuous
fluid-retaining seal 161, more preferably, a pressure-retaining
seal configured to maintain internal chamber 146 (containing
cooling component 150) within a selected pressure range, regardless
of the pressure differential between internal chamber 146 and the
ambient operational environment external of the chamber. Upon
reading this specification, those with ordinary skill in the art
will now appreciate that, under appropriate circumstances,
considering such issues as intended use, component selection,
design preference, etc., other seal arrangements such as, for
example, allowing pressure venting between chamber and ambient,
using seals designed to contain minimal pressure differentials
(such as, earth-surface applications), etc., may suffice.
Both housing 138 and cover plate 152 are preferably constructed
from a lightweight, rigid and appropriately durable material, more
preferably a lightweight metallic material, more preferably a
metallic material having a density of in the range of about 0.003
kilogram/cubic centimeter (kg/cm.sup.3), a thermal conductivity in
the range of about 1.2 Watts/centimeter-Kelvin (W/cm K), and a
specific heat in the range of about 960 Joule/kilogram-Kelvin (J/kg
K). One preferred material suitable for the construction of both
housing 138 and cover plate 152 is `7075` aluminum alloy.
Removable cover plate 152 is preferably retained to open end 140
using a plurality of releasable mechanical retainers, more
preferably a set of externally threaded fasteners 154, as shown. In
the present preferred embodiment, six externally threaded fasteners
154 are evenly distributed about the periphery of removable cover
plate 152, and preferably at least match ASTM-F835 standard
specification for alloy steel socket button-head fasteners (at
least embodying herein at least one second releasable mechanical
retainer).
Cooling component 150 preferably comprises at least one
Phase-Change Material (hereinafter referred to as PCM 160).
Phase-change materials are those that can change from one
physically distinct and mechanically separable state to another
distinct form, such as a crystalline solid to a liquid state. Heat
energy is absorbed during the phase transition, through a latent
energy process. An ideal PCM 160 for the preferred embodiments of
thermal-control system 100 is mass efficient, preferably comprising
high heat capacity and high heat of fusion. In addition, it is
preferred that the selected PCM 160 be chemically stable,
preferably non-flammable, and preferably nontoxic. Based on this
preference set, Applicant selected water as the preferred PCM 160
for use in the presently described preferred embodiments of
thermal-control system 100. It is noted that such a preferred
water-based PCM 160 preferably comprises water or, alternately
preferably, a mixture of water and one or more added substances,
such as, for example, nucleating agents, substances to lower the
freezing point, etc. Upon reading this specification, those with
ordinary skill in the art will now appreciate that, under
appropriate circumstances, considering such issues as operating
environment, intended use, etc., other water-based PCM compositions
such as, for example, water amended with and an equal part of one
or more substances, mixtures comprising water as a minority
constituent of a PCM composition, etc., may suffice.
In addition to the latent heat storage capacity of PCM 160, it is
also preferred that the ice be cooled to at least one temperature
below the isothermic phase-change temperature of the selected
material to obtain additional sensible heat storage capacity. In
the preferred water-based PCM 160 such "super cooling" comprises
cooling the material to at least one temperature below zero-degrees
Celsius, preferably to temperatures ranging between about
-1.degree. Celsius (C.) and about -150.degree. C., more preferably
ranging between about -125.degree. Celsius (C.) and about
-150.degree. C. This preferably allows TCU 102 to comprise
additional sensible thermal storage capacity. Thus, TCU 102 (at
least embodying herein such at least one intermediate structure) is
preferably structured and arranged to assist absorbing the
atmospheric entry heat, generated during return procedure 112, by
implementing both sensible-heat processes and latent-heat processes
(wherein such sensible-heat processes are effected by transition of
PCM 160 from at least one sub-phase-change temperature to a higher
temperature).
The use of a water-based PCM gives the highest heat capacity for
the mass; however, the major disadvantage associated with the use
of water as PCM 160 is the volume expansion of water as it freezes
into ice. This occurs as the polar water molecules align to form
crystalline lattices during transition from a liquid to solid
state. The intended operational environment of TCU 102 requires PCM
160 to be fully contained within housing 138. Because of the
relative large volume expansion and bulk modulus of elasticity of
water to ice, it was determined that large mechanical forces would
be imparted within the necessarily rigid structures of the enclosed
housing 138 as the liquid water was frozen, potentially resulting
in rupture of the container. Furthermore, the preferred
thermal-conduction arrangements of TCU 102 require PCM 160 to be
located and maintained in direct physical contact with at least one
internal wall of internal chamber 146, including during operation
of the device in the micro-gravity environment of space. It is
noted that the preferred gravity-independent operational
requirement of the device precluded partial filling of the chamber
as a preferred option.
The preferred use of a water-based PCM 160 led Applicant to
develop, within cooling component 150, both a volumetric
accommodator function and a PCM locator function to preferably
continuously locate PCM 160 within a selected region of internal
chamber 146. As noted above, to be useable for space applications,
both the volume expansion accommodation function and PCM locator
function of cooling component 150 preferably must operate
independent of gravity.
Applicant's most preferred solution to the problem of PCM
expansion, and the need to specifically locate PCM 160 within
internal chamber 146, was the development and implementation of a
compressible insert 162, preferably configured to reside within
internal chamber 146 in contact with PCM 160, as best shown in FIG.
7.
FIG. 7 shows a partial sectional view, of the sectional detail 7 of
FIG. 5, further illustrating the preferred arrangements of PCTCU
103, with the preferred components of TCU 102 magnified for clarity
of description. Compressible insert 162 is preferably situated
within the forward portion of internal chamber 146 so as to
preferably bias PCM 160 toward closed aft end 142 of housing 138,
as shown. Closed aft end 142 of housing 138 preferably functions as
a heat-exchanging wall 158 structured and arranged to assist
thermal exchange between PCM 160 and the internal thermal
environment 164 of payload compartment 120, as shown (at least
embodying herein wherein such at least one cooling component
further comprises at least one locator structured and arranged to
locate such at least one phase-change material in direct thermal
interaction with such at least one heat-exchanging wall).
Compressible insert 162 preferably comprises at least one
resiliently-deformable material, most preferably resilient
compressible foam, more preferably a resilient compressible foam
consisting of a foamed elastomeric material (elastomeric foam)
having appropriate mechanical flexibility characteristics within
the specified operational temperatures of the device. Upon reading
this specification, those with ordinary skill in the art will now
appreciate that, under appropriate circumstances, considering such
issues as intended use, advances in material technology, etc.,
other a volumetric accommodators such as, for example, compressible
gels, mechanical bellows, flexible container walls, etc., may
suffice.
As the water-based PCM 160 freezes and expands, compressible insert
162 is compressed inside internal chamber 146 (generally toward
cover plate 152). This responsively increases the working volume of
internal chamber 146 during the phase change of PCM 160 from liquid
to solid. Conversely, when PCM 160 melts and contracts, the foam
preferably re-expands, pushing back on the liquid PCM 160, thereby
maintaining PCM 160 in continuous thermal interaction with
heat-exchanging wall 158.
Additionally, the foam material of compressible insert 162 provides
a degree of thermal insulation, thus preferably functioning to
reduce the rate of thermal migration of atmospheric-entry heat
across TCU 102. The insulative properties of compressible insert
162 are also utilized during freezing of PCM 160. In a preferred
on-orbit procedure, TCU 102 is preferably frozen prior to use by
establishing an outward heat flow from PCM 160, preferably by
exposing heat-exchanging wall 158 to at least one below 0.degree.
C. thermal sink. The tendency of the water to becoming "super
cooled" (below 0.degree. C.) yet remain in liquid state increases
in microgravity. This can lead to a sudden and unpredictable
freezing event. Such rapid freezing may overcome the ability of
compressible insert 162 to buffer the volumetric capacity of
internal chamber 146, resulting in a rupture of the container.
Freezing is preferably carried out such that the freezing occurs in
a uniformly controlled manner, preferably by incrementally freezing
PCM 160 substantially in only one direction, preferably from
heat-exchanging wall 158 toward compressible insert 162.
Compressible insert 162 preferably supports this preferred
unidirectional freezing process by thermally insulating the end of
internal chamber 146 opposite heat-exchanging wall 158.
Closed aft end 142 preferably comprises a symmetrical array of
transfer fins 178, preferably projecting from heat-exchanging wall
158 into internal chamber 146 to be engaged within PCM 160. The
array of transfer fins 178 are preferably structured and arranged
to provide at least one supplementary pathway of heat transfer
between PCM 160 and heat-exchanging wall 158. Upon reading this
specification, those with ordinary skill in the art will now
appreciate that, under appropriate circumstances, considering such
issues as PCM volume, phase-change parameters, etc., other fin
arrangements such as, for example, fins having non-parallel
surfaces to assist in breaking up destructive crystalline
structures which form during freezing, etc., may suffice.
In one preferred embodiment of the system, internal chamber 146 of
TCU 102 preferably comprises and overall depth C of about 0.6 inch
with compressible insert 162 comprising a thickness D of about 0.38
inches, the remaining depth E preferably occupied by PCM 160. In
one preferred embodiment of the system, TCU 102 is structured and
arranged to contain about 0.23 kilograms of PCM 160 (about 1/2
pounds). Upon reading this specification, those with ordinary skill
in the art will now appreciate that, under appropriate
circumstances, considering such issues as intended use, foam
properties, etc., other arrangements such as, for example, using
alternate fill ratios, larger or smaller contained volumes,
multiple chambers, etc., may suffice.
TCU 102 further preferably comprises at least one forward coupler
assembly 166 structured and arranged to assist the coupling of TCU
102 with nose cap 121 (or other forward atmospheric-entry structure
of atmospheric-entry vehicle 110). Forward coupler assembly 166
preferably comprises a set of male mounting posts 168, preferably
arranged to project outwardly from mounting points located on the
forward outer periphery of housing 138, as shown. Male mounting
posts 168 preferably comprise the aft portion of Applicant's
preferred mounting system, which are preferably designed to engage
a ring-shaped female mounting component 176 of the forward nose cap
121 (shown diagrammatically by the dashed-line depiction of FIG.
4). Forward coupler assembly 166 was preferably designed with
thermal isolation as a primary goal. Beyond thermal isolation,
forward coupler assembly 166 preferably provides a self-aligning
structural connection adapted to support the anticipated structural
loads generated during return procedure 112.
As illustrated in FIG. 8A, forward coupler assembly 166 preferably
utilizes three male mounting posts 168 symmetrically distributed
around the periphery of housing 138. Each male mounting post 168
preferably projects outwardly from housing 138 to terminate at
distal end 170, which is preferably configured to comprise a
hemispherical contact face 172, as shown. Each hemispherical
contact face 172 preferably comprises an outer radius of about
eight-centimeters.
When forward coupler assembly 166 is operably engaged, each
hemispherical contact face 172 bears on a concave mating surface of
female mounting component 176, most preferably at a single point of
contact. The above preferred arrangement effectively reduces
thermal conduction between the forward and aft vehicle structures
by limiting the area of contact to three small points, as shown.
Because the primary heating phase occurs in near vacuum (in space),
thermal conduction is the major mechanism of heat transfer; thus,
the above-described arrangement preferably functions as a thermal
isolator 174 to thermally isolate non-coupled portions of TCU 102
from the atmospheric-entry heat generated by the forward
atmospheric-entry structure during atmospheric entry.
It should be noted that a structural design feature of forward
coupler assembly 166 is that the connection between male mounting
posts 168 and the female mounting component is not perfectly rigid;
thus, thermal contact areas arise that are hardness dependent.
Therefore, mount materials are preferably made of, or coated with,
very hard metals to assist in controlling the overall thermal and
structural performance of the mount. The materials used in the
principal components of forward coupler assembly 166 have a
preferred Rockwell hardness of between about 60 and about 70. The
structure(s) between the male and female mounts preferably are
designed to withstand system loads causing the entire structure to
operate as a pseudo rigid-body. In a preferred embodiment of the
present system, male mounting posts 168 comprise a metallic
material having a density of in the range of about 0.004
kg/cm.sup.3, a thermal conductivity in the range of about 0.07 W/cm
K, and a specific heat in the range of about 522 J/kg K. A
preferred material suitable for the construction of male mounting
posts 168 preferably comprises titanium alloy.
During experimental development, Applicant determined an acceptable
contact area between male mounting posts 168 and the female
mounting component to be about 0.0012 square inches each. A
computer-assisted thermal model was constructed by the Applicant to
determine the effective thermal resistance for each male mounting
post 168. The results of the thermal model analysis indicated an
effective thermal resistance for the assembly of about 108 C/W when
using titanium and the physical geometric arrangements described
above.
TCU 102 preferably comprises at least one aft coupler assembly 180
to couple detachably TCU 102 to open forward end 132 of payload
section 124 and payload compartment 120, as shown. A preferred
function of aft coupler assembly 180 is to position heat-exchanging
wall 158 in thermal interaction with the internal thermal
environment 164 of payload compartment 120 (at least embodying
herein wherein such at least one aft coupler comprises at least one
postioner structured and arranged to assist positioning of such at
least one heat-exchanging wall in thermal interaction with at least
one thermal environment of the at least one payload compartment).
In addition, aft coupler assembly 180 is preferably adapted to
support the operation of TCU 102 as a detachable lid 134 for
payload compartment 120.
Aft coupler assembly 180 preferably comprises a plurality of
releasable mechanical retainers, more preferably a set of
externally threaded fasteners 182, as shown (at least embodying
herein wherein such at least one aft coupler comprises at least one
first threaded retainer structured and arranged to assist threaded
retention of such at least one payload-compartment lid to the at
least one open forward end of the at least one payload
compartment). Other fastener-related hardware, such as washers,
thread-lock materials, etc. are preferably included within the
assembly, as shown. Those with ordinary skill in the art will now
appreciate that upon reading this specification and by their
understanding the art of fastener attachment as described herein,
methods of attaching such washers, lock-nuts, etc will be
understood by those knowledgeable in such art.
Housing 138 preferably comprises aft mating surface 184 (see FIG.
8B) structured and arranged to assist forming at least one mated
engagement with a circumferential mounting ring 186 of forward end
122. In the present preferred embodiment, 12 externally threaded
fasteners 182 are evenly distributed about the periphery of housing
138, and are preferably captured rotatably within a set of
peripheral apertures, passing through aft mating surface 184 to
threadably engage mounting ring 186, as shown (at least embodying
herein at least one first releasable mechanical retainer structured
and arranged to assist releasable mechanical retention of such at
least one intermediate structure to the at least one open forward
end of the at least one payload compartment). Upon reading this
specification, those with ordinary skill in the art will now
appreciate that, under appropriate circumstances, considering such
issues as cost, intended use, etc., other fastening arrangements
such as, for example, releasable clamps, threaded engagements,
permanently sealed containers, etc., may suffice.
Mounting ring 186 of payload section 124 preferably comprises at
least one pressure-retaining seal, preferably O-ring seal 188
located in circumferential channel 190, as shown. When aft mating
surface 184 is secured to mounting ring 186, O-ring seal 188
preferably assists in maintaining a generally isobaric pressure
level within the internal thermal environment 164 of payload
compartment 120. This preferably forms payload compartment 120 into
a sealed pressure vessel 126.
During experimental development, Applicant generated
three-dimensional thermal computer models to examine heat transfer
phenomena of the proposed TDRV 115 design with regard to the
preferred PCTCU 103 and TCU 102 component during entry stage 118.
The model of TDRV 115 provided preliminary data associated with
temperature extremes that vehicle components are expected to
encounter for this operational stage. A general description of the
experiment is provided herein to further the understanding and
enablement of TCU 102, in the context of a preferred implementation
of the invention.
A transient thermal model was created by the Applicant using
THERMAL DESKTOP.RTM. (ver. 5.2). It comprised a three-dimensional
model of the mid portion of TDRV 115, assuming PCTCU 103 to be
empty. Structurally, it consisted of the exterior shell of TDRV
115, payload section 124, its exterior casing (omitted from the
illustrations for clarity), TCU 102, forward coupler assembly 166
(male and female components), and the PCM 160 incorporated within
TCU 102. PCTCU 103 was modeled with TET (Tetrahedral) elements for
the mounting ring 186 and the mid-plate 130 (which separates
payload compartment 120 from aft section 128) and with 2-D shell
elements for the forward and aft cylinders of payload compartment
120 and aft section 128. The sections were connected via contactors
that simulated continuity of the part.
TCU 102 was likewise modeled with TET elements, and the outer
casing and adjacent structures of TDRV 115 were modeled as shell
elements. As previously noted, male mounting components of forward
coupler assembly 166 were preferably represented as thermal
conductors. The model neglected the thermal mass of the mounts, but
the effect on the transient response was expected to be slight with
regard to the significant thermal mass of the adjacent TCU 102.
PCM 160 was preferably represented by a boundary node with a fixed
temperature for the purpose of analysis. The temperature was held
at the phase-change temperature (0.degree. C., for assumed
water-based PCM 160). The total heat transferred to this node was
compared to the latent capacity of water for the available volume
to validate the assumption.
The thermal model was simplified to omit nose cap 121, with its
associated avionics and components, the aft avionics and parachute
package, the aft mounts, and the aft body with attached flare 116.
As the goal of Applicant's analysis was to evaluate potential
thermal risk to payload 104, these components were not considered
critical to the scope of the analysis. The aft avionics heat
dissipation load was however accounted for. The full avionics
dissipation (about 5.345 W) was assumed to sink into the aft
cylinder in a circumferential band, encompassing a ring of
calculated thermal nodes, aft of mid plate 130 (about 2 cm to 4 cm
back from the plate).
The missing components are considered thermally remote from payload
compartment 120 and payload 104. For example, nose cap 121 is
preferably separated from the forward avionics by standoffs and
preferably from PCM 160 by male mounting post 168 of TCU 102.
Additionally, the preferred interstitial insulation 199 was not
modeled within the casing enclosing PCTCU 103. Using a multi-layer
insulation 199 in the casing design would further decrease the
effective emissivity of the enclosure, thereby producing an even
more robust solution in the eventual vehicle design. The outer
shell of the proposed TDRV 115 is likely to comprise carbon-carbon
composite thermophysical properties (parallel to fiber direction),
and the inner cylindrical walls of payload section 124 (comprising
pressure vessel 126) is preferably constructed of aluminum
`2024`.
Pressure vessel 126 and TCU 102, and the casing edge and PCTCU 103
are assumed to have no effective thermal resistance in their
respective mated surfaces. For the purpose of the analysis, PCM 160
was assumed to be in intimate contact with the three plate surfaces
of the exterior of TCU 102, and not with the flanges/webs, through
the use of a large valued conductor. The gap between the vessel and
casing was assumed to be voided and to provide an effective,
combined emissivity of about 0.01 for the enclosure (facing
anodized surfaces of about 0.1 emissivity). A vacuum gap was also
assumed to be present between mounting ring 186, TCU 102, and
casing and the shell of TDRV 115, providing an enclosure emissivity
of about 0.088. The exterior of TDRV 115 was assumed to have an
emissivity of about 0.88.
All structures were assumed to have an initial temperature of
0.degree. C., modeling a frozen water-based PCM 160 without "super
cooling". Two analyses were made: one with PCM 160 active and
another without the benefit of PCM 160. The "with PCM"
configuration is considered the baseline for the present
system.
The exterior of TDRV 115 was assumed to radiate to a constant sink
temperature of about 25.5.degree. C. (representative of a median
Earth temperature, and assumes no space view or flare component).
The re-entry environment is simulated via the application of a heat
flux load on the exterior of TDRV 115 representing a typical entry
profile.
The thermal model determined that while the double vacuum gaps
provide a significant radial temperature gradient, the exterior
(female) mount temperature closely tracks the external temperature;
however, interior component temperature profiles, including the
interior (male) mount point temperature, was observed to be
substantially lower. The change of temperature was found to be
relatively small (<7.degree. C.), both from radiation to the
cylinder walls and from conduction through the mounts.
The analysis clearly showed that PCM 160 is critical for this
result, as heat from the mounts is conducted into PCM 160, rather
than contributing to a temperature rise within TCU 102. This is
demonstrated by comparing the modeled temperatures for PCTCU 103
"with" and "without" PCM 160. Heat load compensation by PCM 160 was
profiled in the analysis and was found to comprise a total energy
equivalent of about 16.9 kJ. As the heat of fusion for ice is 333
kJ/kg, approximately 0.05 kg (0.112 lbs) of the water-based PCM 160
was expended during the simulated entry stage 118. This is weighed
against the approximate 0.46 pounds of ice that above-described
embodiment of TCU 102 preferably holds.
The other component temperatures were found to be effectively
independent of PCM 160, as the vessel walls of PCTCU 103 proved
thin enough not to conduct significant heat as to affect the
temperatures in the bulkier sections, and vice versa.
Applicant's analysis suggests that keeping PCTCU 103, and thereby
payload 104, from any significant temperature rise during entry
stage 118 is fully feasible using the preferred embodiments of the
system. Temperatures of pressure vessel 126 were predicted to
increase approximately 2.degree. C., and payload 104 will be
further isolated by internal insulation. The preferred design of
TCU 102 as integrated within PCTCU 103 effectively retarded heat
flow from the external shell of TDRV 115 by conduction through the
mounts and by radiation across the voids to the main body of PCTCU
103. The necessity of the preferred TCU 102 design containing PCM
160 to absorb heat conducted through the mounts was demonstrated by
the thermal analysis. Furthermore, as entry stage 118 was
considered the primary heating contributor, and PCM 160 was
exhausted by less than a fourth of its capacity, the effectiveness
and utility of the preferred design was confirmed.
FIG. 8A shows a plan view of the forward structures of TCU 102,
according to the preferred embodiment of FIG. 2. FIG. 8B shows a
plan view of a preferred arrangement of aft mating surface 184 of
TCU 102, according to the preferred embodiment of FIG. 2.
FIG. 9 shows an extra-vehicular activity suit (EVA suit 200)
comprising a portable life support system (PLSS 203) utilizing at
least one Thermal Control Unit (TCU 202), according to an alternate
embodiment of the present invention. On Jul. 20, 1989, the 20th
anniversary of the Apollo 11 Moon landing, George H. W. Bush, then
President of the United States, announced plans for what came to be
known as the Space Exploration Initiative. With the advent of the
Exploration Initiative, and its stated goal to perform long-term
research on the moon, the logistics imposed by an expendable
thermal control system are daunting. For example, assuming 24-hours
of Extra-Vehicular Activities (EVAs) per week, and assuming a 400 W
average heat load (300 W metabolic +100 W equipment), for a
six-month period, a total of 359 kg of water would need to be
expended per astronaut, which equates roughly to a total of about
718 kg (0.79 ton) for two crew members.
An additional goal is to be able to perform EVAs anywhere on the
lunar surface, which presents challenges for the potential use of
conventional radiator technologies, due to the hot thermal
environment at and around the sub-solar point. In contrast, a
PCM-based EVA cooling system has the advantages of no consumables
and operation independent of the local radiation thermal
environment. A phase change material such as PCM 160 can absorb the
heat for later rejection between EVA operations.
FIG. 10 shows a rear view, diagrammatically illustrating the
integration of TCU 202) within a wearable "pack" containing PLSS
203 of EVA suit 200, according to a preferred embodiment of the
present invention. FIG. 11 shows a sectional view, through the
section 11-11 of FIG. 10, generally illustrating preferred
component arrangements of TCU 202, according to the preferred
embodiment of FIG. 10.
TCU 202 preferably comprises PCM 160 configured as a heat sink,
preferably utilizing "super cooled" ice as a non-toxic,
non-flammable PCM within PLSS 203. As previously discussed, the
latent heat of fusion for water is relatively large. Further mass
reduction is preferably accomplished by cooling the ice
significantly below its freezing temperature for additional
sensible heat storage. Expansion and contraction of the water as it
freezes and melts is accommodated with the use of a flexible
internal membrane 204 and compressible foam liner 206, as
shown.
The concept of the use of TCU 202 is that the unit is preferably
cooled within some support station of the vehicle from which the
EVA will be initiated. TCU 202 is preferably installed within the
system once the EVA suit coolant system is running and an
appreciable heat load is being generated. An astronaut would then
rely on TCU 202 as a heat sink for the duration of the EVA or swap
a completely melted pack with a fresh, super cooled replacement
pack, depending on the thermal storage capacity of the pack and the
EVA duration. After TCU 202 is removed from the suit support system
(usually PLSS 203) it is preferably frozen by cooling PCM 160 to
below 0.degree. C. for the next use. All of these operational steps
would impose requirements on TCU 202, such as the accommodation for
installation, the sloshing and other movement inherent in a
backpack-mounted system, and predictable thawing/heat absorption
during the duration of the ice temperature rise, conversion of the
fluid to liquid form, and final heating to the maximum usable
temperature.
As with the prior embodiment system, the preferred PCM is water.
Water's inherent high heat capacity and high heat of fusion
combined with its non-flammable, nontoxic characteristics makes it
an ideal candidate for PCM 160; however, the major drawback is
again the expansion of water into ice when it freezes. This
expansion presents problems of containment, and possible rupture of
the containment vessel. Through experimentation, Applicant has
solved this problem by the use of a flexible membrane material
coupled with a flexible foam material to accommodate the expansion
and contraction of the water as it freezes and melts.
To take advantage of the large heat capacity of ice, and to further
reduce the mass of water required, it is desirable to "super cool"
the PCM below the freezing temperature by exposing PCM 160 to very
low temperatures (preferably between about -125 K and -150 K).
Through empirical testing, Applicant demonstrated the functional
utility of the preferred TCU 202 that allowed for water expansion
and contraction during repeated freeze/thaw cycles occurring
between about 20.degree. C. and about -150.degree. C.
One of the challenges for using a PCM in a PLSS is to balance the
trade between thermal capacity (duration) and on-back weight. A
PCM-based unit with enough thermal capacity for a full eight-hour
EVA has an advantage of requiring no mid-EVA change-out and its
associated overhead. However, such a PCM-based unit may result in a
PCM mass that is too large from the perspective of center of
gravity and/or on-back weight. Assuming an average heat load of 400
W (300 W metabolic +100 W equipment), and depending on the
additional sensible energy available by super cooling the PCM to
below 0.degree. C., an eight-hour EVA would require about 20 kg-25
kg of water-ice. This calculation does not include the additional
mass of the packaging of TCU 202, which adds as much as one to two
times as much mass as PCM itself. Based on this analysis, Applicant
focused on achieving a four-hour EVA duration thermal capacity for
TCU 202.
Referring again to FIG. 9, two potential locations of TCU 202 are
available, both preferably located within region 208 of EVA suit
200, as shown. These preferred locations preferably comprise the
bottom of the PLSS 203, as shown in FIG. 10, or alternately, on the
front of the suit across the waist-belt region 210. Using a maximum
length of 23 inches, based on the approximate width of the current
PLSS designs, a preferred capacity of about 16 kilograms (kg) of
water-based PCM 160 is possible, accounting for accommodation
requirements associated with other subsystems of PLSS 203. In one
preferred embodiment of TCU 202, this volume of PCM 160 is
preferably packaged within container 212 having the approximate
physical dimensions of about 23 inches.times.about 6.5
inches.times.about 6.5 inches (thus enabling a preferred internal
capacity of about 972 cubic inches).
This preferred "pack" supported embodiment of TCU 202 preferably
comprises at least one fluid-retaining boundary 201, in part formed
by the flexible internal membrane 204, more preferably comprising a
flexible bag 214, preferably located internally within container
212, as shown (at least embodying herein at least one
fluid-retaining boundary structured and arranged to retain the at
least one phase-change material in the at least one liquid state
and the at least one solid state). Flexible bag 214 is preferably
structured and arranged to retain PCM 160 within container 212
while in both the liquid state and the solid frozen state.
Container 212 preferably functions as a protective outer shell to
protectively enclose portions of such fluid-retaining boundary
including flexible bag 214, as shown. The outer shell of container
212 preferably comprises a rigid composite material having a fixed
external volume.
TCU 202 further comprises at least one heat-transfer interface 216
structured and arranged to establish at least one physical
interface enabling heat transfer across the fluid-retaining
boundary within container 212. In one preferred arrangement of TCU
202, heat-transfer interface 216 comprises a thermally-conductive
cover plate 218, which may preferably comprise one or more
heat-transfer structures, such as, for example, passages for the
circulation of secondary coolants, thermocouples, sensors, etc.
Depending on selected weight restrictions within PLSS 203/EVA suit
200, copper may be selected as a preferred material for use in the
construction of cover plate 218, due to its high thermal
conductivity.
The thermally-conductive cover plate 218 preferably comprises at
least one heat-transfer assister 220 in the preferred form of a
plurality of projecting fins 222, as shown. Fins 222 are preferably
structured and arranged to be embedded within multiple locations
within PCM 160, as shown, to assist heat transfer between PCM 160
and the supplied heat-transfer interfaces of cover 218 (at least
embodying herein at least one heat-transfer assister structured and
arranged to assist heat transfer between the at least one
phase-change material and such at least one heat-transfer
interface). Each projecting fin 222 preferably comprises a
plurality of heat-exchanging surfaces 221, each one structured and
arranged to assist exchanges of heat energy between PCM 160 and its
respective projecting fin 222, as shown.
Each projecting fin 222 preferably comprises proximal end 232,
preferably joined with cover plate 218, and at least one distal end
234, as shown. Projecting fin 222 preferably comprises a
longitudinal length `L` separating proximal end 232 and distal end
234, as shown. Projecting fin 222 preferably comprises at least one
parallelogram-shaped lateral cross-section 226 within longitudinal
length `L`, as best shown in FIG. 12. In addition, each projecting
fin 222 preferably tapers from proximal end 232 to distal end 234,
as shown in FIG. 11.
FIG. 12 shows a sectional view, through the section 12-12 of FIG.
11, generally illustrating preferred component arrangements of TCU
202, according to the preferred embodiment of FIG. 10. Flexible bag
214 preferably comprises a plurality of interior surfaces in direct
physical contact with PCM 160, as shown. The function of the
diaphragm-like flexible bag 214 is to allow for the expansion and
contraction of the water as it freezes and thaws. A compressible
foam layer 223 is preferably supplied between flexible bag 214 and
inner wall surfaces of container 212, as shown. Compressible foam
layer 223 inside container 212 compresses as the water-based PCM
160 freezes and expands.
Material selections for flexible bag 214 was challenging due to the
extremely low temperature (approximately -150.degree. C.) to which
the material must be useable (resulting in a derived requirement of
an extremely low glass transition temperature). Additionally, the
material of flexible bag 214 must not be permeable to gas.
Applicant's original concept was to use an elastic material that
would accommodate the volume changes by stretching elastically.
Such materials investigated included Viton.COPYRGT. fluoroelastomer
and low-permeability silicone; however, with subsequent testing,
and the preferred incorporation of a compressible foam liner 206
into the preferred design, the material focus switched to diaphragm
materials that are flexible, but not necessarily elastic. These
preferred materials were demonstrated to accommodate the volume
changes of the water, but instead of stretching, they simply fold
(crinkle) and unfold, as suggested in the illustration of FIG. 13.
Through analysis and testing, Applicant selected a commercially
available polyvinyl fluoride (PVF) sheet as the most preferred
material for flexible bag 214. The selected material is flexible
down to about -100.degree. F. (-73.degree. C.), and usable from
about -385.degree. F. (-231.degree. C.) to about 225.degree. F.
(107.degree. C.) with intermittent spikes to about 400.degree. F.
(204.degree. C.). Although the flexible temperature limit
(-73.degree. C.) is not as low as the expected useable lower
temperature limit (-150.degree. C.), most of the volume change
occurs with the phase change between solid and liquid at 0.degree.
C.
Foam liner 206 preferably provides a resiliently-deformable member
providing at least one region of resiliently-deformable volumetric
expansion between such at least one expandable fold and such at
least one outer shell. The minimum volume increase provided by
compression of foam liner 206 is preferably equal to the maximum
calculated volume increase of PCM 160 after freezing. Although
volumetric accommodation is the primary function of the foam, the
foam envelope provides some degree of insulation for PCM 160.
FIG. 13 shows a partial sectional view, of the sectional detail 13
of FIG. 12, magnified for clarity of description. Flexible bag 214
is preferably sized and configured so as to preferably form a
plurality of expandable folds 224 within the flexible walls of the
bag, particularly when PCM 160 is in a liquid state. These
expandable folds 224 (crinkles) are preferably structured and
arranged to assist articulated expansion of portions of flexible
bag 214 to accommodate volumetric changes of PCM 160 during phase
transition from liquid to solid and back. The preferred use of
folds within the fluid membrane effectively resolves the issue of
poor mechanical flexibility within the bag materials when PCM 160
is cooled to a temperature below 0.degree. C. for additional
sensible heat capacity.
Referring again to FIG. 12, an important feature of presently
disclosed embodiment of thermal-control system 100 is controlling
the movement of ice during the freezing process to reduce stresses
associated with phase-change expansion. This is necessary to allow
the use of water as a mass-efficient PCM 160 within the relatively
larger PCM capacity of TCU 202.
In a highly preferred arrangement of the system, projecting fins
222 are preferably configured to comprise what may be characterized
as a "mechanical disrupter" 230 structured and arranged to assist
mechanical disruption of frozen crystalline lattices occurring
within PCM 160 during the phase-change transition from the liquid
state to the solid state. Such a mechanical disrupter 230 is
preferably generated within PCM 160 by arranging the
heat-exchanging surfaces 221 of each projecting fin 222 in a
specific non-parallel arrangement, as shown. This highly preferred
configuration organizes each projecting fin 222 to comprise
parallelogram-shaped lateral cross-section 226, as shown. Such a
preferred "diamond" fin shape provides groupings of sloping
surfaces that function to "push" ice away from adjacent surfaces
during freezing.
In more specific terms, each heat-exchanging surface 221 comprises
at least one non-parallel orientation relative to all opposing
adjacent interior surfaces of the plurality of interior surfaces of
flexible bag 214 and all opposing adjacent heat-exchanging surfaces
221 of the fins, as shown. Such non-parallel orientation of
respective opposing surfaces produces mechanically-disruptive
movement of the crystalline lattices occurring within PCM 160
during phase-change transition from the liquid state to the solid
state.
As PCM 160 freezes outwardly from heat-exchanging surface 221, the
rigid ice structure eventually intersects an adjacent opposing
surface. Because the opposing adjacent surfaces are non-parallel,
the lines of action developed by the expanding ice between the
surfaces include non-normal force vectors, which produce
pressure-reliving movements of the ice as it is "squeezed"
outwardly from between the rigid structures, as shown. In addition,
this preferred arrangement provides sharp angular edges 236 that
preferably function to break up (cleave) the crystalline lattices
of the ice during freezing. This preferred geometric configuration
eliminates the potential for destructive entrapment of ice by
eliminating adjacent parallel planar surfaces (at least embodying
herein wherein each heat-exchanging surface comprises at least one
non-parallel orientation relative to all opposing adjacent interior
surfaces of such plurality of interior surfaces and all opposing
adjacent heat-exchanging surfaces of such plurality of
heat-exchanging surfaces; and such non-parallel orientation of such
respective opposing surfaces produces mechanically-disruptive
movement of the crystalline lattices occurring within the at least
one phase-change material during such at least one phase-change
transition from the at least one liquid state to the at least one
solid state).
Upon reading this specification, those with ordinary skill in the
art will now appreciate that, under appropriate circumstances,
considering such issues as intended use, terrestrial needs, etc.,
other PCM arrangements such as, for example, instantaneous cooling
in automobiles, may suffice. In such an arrangement, a PCM unit
could be adapted to allow for instantaneous cooling in automobiles.
In hybrid and electrical vehicles, substantial amounts of the
electrical storage of the battery are used for initial cooling of
the automobile interior. Furthermore, the use of PCMs would extend
the range of the vehicle or reduce the size of the batteries. These
advantages would provide a market-derived benefit for the companies
that employ these techniques. Secondary useful applications may
also include thermally-controlled suits for firefighters and
similar extreme-environment cooling applications.
Although applicant has described applicant's preferred embodiments
of this invention, it will be understood that the broadest scope of
this invention includes modifications such as diverse shapes,
sizes, and materials. Such scope is limited only by the below
claims as read in connection with the above specification. Further,
many other advantages of applicant's invention will be apparent to
those skilled in the art from the above descriptions and the below
claims.
* * * * *